After very long back and forth superior, I have decided for this lens. I use it for my 50D. The purchase was not easy. I was looking for a very good Always plan "You could choose various lenses:.. Powerful with 2.8 Canon Tamron, Tokina and Sigma I have many tried in various photo stores and friends in the shortlist finally stood the EFS 17-55 2.8. IS USM and the 24-105 4 L. The Sigma Tamron and Tokina eliminated for various reasons from (poor image quality, poor haptics etc.) If you look at the lens hood and the original lens case to buy from the EFS, one also reaches a high price. When 24-105 4 L both are included. In addition, you can use the EFS only for crop sensor cameras. The 24-105 L won the comparison. The quality is just great. Dripping water and dust, all important parts and the tube are made of metal. It has a solid working tool in hand. Lens hood sits firmly and the lens. It may be that a continuous transition Duch aperture of 4 is not the fastest lens. Thanks to the stabilizer (IS), but you can make it up for it to a certain degree. Who is mainly photographed in darker rooms have limited enjoyment of the lens. Here it is better to buy one with Aperture 2.8 or greater. I with my camera by a factor of 1.6 (= 24mm 38,4mm / mm format) have, this lens has virtually no wide angle. Is not annoying for me because I have an extreme wide-angle for landscapes and architectural shots.
For real: The picture quality: That's just amazing. I had quite good lenses, but this beats them all worlds. Thanks to the ultrasonic motor (USM) focusing is very fast, very quiet and very precise. I have due to the uncertainty almost no committee Photos ". The images are very Contrast, have vibrant colors and are knackscharf. I had to edit my old lenses almost all the images in Photoshop and they were still not as good as the raw of this lens. Not only the camera is important. Today's DSLR cameras, whether entry-level cameras for 400 Euro or top models for 3500 euro are making very good to great pictures. However, a prerequisite for this is a suitable lens. I did it with this type available.
Conclusion: Absolute buy recommendation. Prefer to invest more money in a lens and continued enjoyment have it. Usually survived "an objective several camera model change. For example, I still have very good lenses on his back almost 15 years.
Another tip for last: This lens (like all non-EFS lenses) can be used on all EOS models. So if you want later to upgrade to a one-digit EOS camera, this lens can also continue to use.
